Brush structure



Sept. 29, 1942. c. ROBERTS BRUSH STRUCTURE Fild'July L25, 1940,

ill will I //V l/ENTUQ Patented Sept. 29, 1942 BRUSH STRUCTURE Clifford Roberts, Winchester, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application July 25, 1940, Serial No. 347,435

4 Claims.

This invention relates to brush structures, and particularly those of the type in which the brush elements are supported by a channel strip of indefinite length. Such structures may then be utilized to form hand brushes of various shapes or may be wound helically to form a cylindrical rotary brush.

In making brush structures of the strip type, in which the brush elements, which will hereinafter be referred to as bristles-although they may be of any suitable materialare doubled around a core and the bend or doubled portion of the bristles clamped in a channel strip, there are various features which make some such brush strips more desirable than Others. The bristles must be held against displacement longitudinally of the strip so that a uniform distribution of bristles will be maintained. There must be an opportunity, nevertheless, for a slight breathing movement of the bristles in the throat of the channel strip to permit the bristles to assume a natural position and to avoid having bending points which are too sharply defined. In other words, if the bristles are gripped up to a certain definite point and beyond that they are not held at all, then any deflection of the bristles causes them 'to bend always at this particular point and renders breakage more likely. There is, furthermore, the danger that the bristles will be cut by rubbing contact with the edges of the channel strip, which, if the strip is made of sheet metal, may be relatively sharp.

With these considerations in mind, an object of the invention is to provide an improved brush strip structure which will wear longer and will feel better to the touch. In the illustrated construction, the bristles are doubled about a core of resilient and/or plastic material, and a protective strip of plastic sheet material such as rubber is interposed between the doubled portions of the bristles and a channel strip. This channel strip is here shown as formed by bending a fiat strip.

In the accompanying drawing, in which the single figure is an angular view showing also a cross-section through a brush strip, the brush structure comprises a series of bristles I'll which may not be animal bristles at all but may comprise wires, threads, pieces of hair, vegetable fibres, or any desired brushmaking material. These bristles are doubled into U shape over a core l2, being held within a sheet metal channel strip M between which and the bristles is interpositioned a liner strip I 6 of resilient and/or plastic material. A suitable grade of rubber may be employed for either the core l2 or the liner I6, but the exact material is not of the essence in this invention.

It will be recognized that, by reason of the limited width of the channel after it has been bent around the bristles in the usual fashion, the bristles which contact with the core l2 tend to indent the core slightly and that there will thus be a real hindrance to displacement of the doubled portions of the bristles lengthwise of the strip. Furthermore, the yielding nature of this core assists in avoiding breakage of the bristles at any point in the doubled middle portions thereof. The liner I6 permits the bristles to breathe or rearrange themselves slightly at the throat N3 of the channel strip. Also, the danger of rubbing contact between the bristles and the relatively sharp inner edges of the metal strip is avoided because of the interpositioning of the resilient liner I6. This also results in making the bend between the free portion of the bristles and the portion which is tightly gripped by the channel strip I4 less fixed and definite and thus avoids the rapid breakage which would accompany bending of the bristles at a permanently fixed point. If desired, a coating of a suitable kind of adhesive may be applied to the core 12 before the latter is associated with the bristles, thus adding to the ability of that core to prevent displacement of the bristles along the core. It may also be found convenient to cement the liner I 6 to the channel strip I 4 before the latter is bent into the illustrated shape around the folded bristles.

Such brush strips are sometimes bent into rectangular or other shape to provide hand brushes, floor brushes, and a wide variety of articles. It is also an established practice to utilize such brush strips by winding them in helical form about an arbor thereby to provide a cylindrical rota y brush which may be made up of any diameter and of any length desired from a supply brush strip of indeterminate length.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A brush structure including a channel strip of sheet metal, bristles gripped within and projecting from said channel, and a layer of soft, resilient plastic material interposed between the sides of the channel and the bristles and prov tecting the bristles from wear against the inner corners of said channel strip.

2. A brush structure comprising an extended bundle of U-shaped flexible bristle elements, a soft, indentable plastic core within the bend of said U-shaped bristle elements, and a channel strip of sheet metal surrounding the bend of said bristle elements and said core, the width of said channel being such that some of the bristles are pressed into the surface of the core.

3. A brush structure comprising an extended bundle of U-shaped flexible bristle elements, a plastic, homogeneous, solid core within the bend of said U-shaped bristle elements and soft enough to be indented to receive a singl bristle, a rigid channel strip surrounding the bend, or:

' said bristle elements and said core, and resilient,

CLIFFORD ROBERTS. 

